Electric space heater



March 17. 1925.

T. C. RUSSELL ELECTRIC SPACE HEATER Filed Oct. 12, 192.5

I I INVENTOR.

TTORNEYS.

Patented Mar. 17, 1925.

arteries 0. RUSSELL, or cmoaeo, rumors.

ELECTRIC SPACE HEATER.

Application filed October 12, 1928. Serial No. 668,069.

To all whom it may concern:

. Be it known that I, THOMAS C. RUSSELL, a citizen of the United States, and a resident of Chicago, in the county of Cook and State of Illinois, have'invented certain new and useful Improvements in Electric Space Heaters, .of which the following is a specification.

My invention relates to electrical space heaters and covers improved construction and arrangement of the heating element therefor. The invention is concerned particularly with the type of element in which the resistance filament, wire or ribbon is enclosed in a long, flat,;metallic sheath and connected at its ends with terminal connectors at the ends of the element.

' In some of the prior art elements of this class the back wall at each end of the sheath is extended longitudinally to form a support for the terminal connectors and also for means by which the element may be mounted in housings or panels. Such arrangement needlessly increases the length of the element and incurs wastage of metal and space both in the element and the support ing panel or housing structure therefor. The important object of my invention is to provide construction and arrangement which will effect great saving in material both for the element and its enclosing housing or panel structure, and without any loss of electrical efficiency. This I accomplish by clamping terminal supporting structures transversely around the ends of the element sheathing, thus eliminating the extensions on the sheathing made necessary in prior constructions, and keeping the terminal connectors and their supporting structures entirely within the ends of the sheathing. At the same time I secure supporting standards or brackets to the element in common with the terminal supporting structures, also entirely within the ends of the element. This material shortening of the element without in a-nywise disturblng its electrical capacity or efiiciency enables the use of much smaller and more compact supporting or enclosing structures for the elements with resulting economy in material, space and expense.

On the accompanying drawing I show my improved construction and arrangement and on this drawin Fig. 1 is a slde elevational view,

Fig. 2 is an edge elevational view with one end in section on plane 22, Fig. 1,

View showing the supporting The long flat sheath S is formed of suit able sheet metal, the side sections A and B being turned over into parallelism with the back C. Extending longitudinally through the sheath are one or more heating units 10 of sultable resistance material and which maybe in the form of resistance wire bent in zlgzag fashion as shown in Fig. 5. The heating units or ribbons are insulated from each other and from the sheathing by a wrapping of insulating material such as mica 11 which preferably extends a short distance beyond the ends of the sheath. At the ends of the resistanceribbon are secured the terminal straps 12 having connecting holes 13 at their outer ends and at their inner ends extending a short distance into the sheathing to be suitably connected with the ends of the resistance ribbon as shown in Fig. 5. Befo-rethe sheathing sides A and B are turned down a pressure plate D is applied on top of the insulation and against this plate the sides A and B are turned down with sufficientv pressure to securely compress the resistance ribbons secured in place within the sheathing and insulation. The sheath may be of a width to accommodate an desired number of resistance ribbons. 0 such ribbons are shown and such ribbons, as will be explained more fully later, may be. conveniently connected in series or in parallel or used separately as desired depending upon the heating service r uired.

ach terminal sup-porting structure comprises upper and lower clamping blocks 14 and 14' which blocks may be similar and are preferably moulded of some insulating fireproof material such as asbestos. These clamping blocks extend transversely across the ends of the sheath S and are drawn together at their ends by clamping bolts 15 to securely clamp the sheath and be thus rigidly held in place thereon. To more accurately position the blocks and prevent displacement thereof the blocks have the lower I steps or seats 16 between which the respective end of the sheathis received, and the blocks have intermediate steps or seats 17 for receivin the projecting end 11 of the sheath insulating material, while between the opposed upper steps or seats 18 extend the terminal straps 12. When the upper and lower blocks of a structure are brought together to receive the sheath end, they are applied so that the sheath endwill abut against the step 17 and the insulation 11 against the step 18, and the blocks Wlll. then be in accurate position ready to be clamped together.

The blocks have the transverse channels 19 on one side for accommodating the terminal straps 12, these straps being bent around through these channels and then across the top of one of the blocks, in this case the block 14. The blocks have the bolt passageways 2O countersunk from the inner side as indicated at 21, and through these passageways bolts 22 extend, the bolts also extending through the holes 13 in the terminal straps which are brought into register with the passageways when the straps are bent around the blocks. A suitable terminal structure 23 is also applied to each bolt before the bolt nuts are applied, the bolts then intimately securing the ends of the terminal straps to the blocks and the terminal structures in intimate electrical engagement w1th the strap ends. The ridge 25 between the channels 19 insulates the straps from each other at the side of the block and a similar ridge 26 is provided on the outside of the block for continuing the insulation between the terminal straps and also to prevent electrical contact between the adjacent terminal structures 23. The terminal structures 23 shown are of a well known spring clamping type and need no further description. They are preferably applied to extend inwardly from the clamping structures so as not to take up any space outside thereof and so increase the length of the element.

In Figs. 2 and 3 I show simple means for supporting an element on panels or within housings. The supporting brackets 27 shown are in the form of flat bars which reccive the ends of the clamping screws 15 to be drawn thereby rigidly against the backs of the blocks 14 of the terminal supporting structures, the lower ends of the bars being deflected to form seats 28 by means of which the can be readily secured to a support suc as a panel P by screws 29. The bars have the deflections 30 for clearing the ridges 26 on the blocks. The bars also serve the important function of strengthening the blocks when they are brought together to clamp the sheathing.

\Vith my improved construction and arrangement the entire length of an element is practically only that of the sheath which contains the resistance ribbon, and terminal supporting and element securin extensions on the sheath are eliminated. t is evident therefore that the supporting panel or housing structures can be made very much smaller with less material and space and without any loss of electrical efficiency or heating capacity. There may be one or more resistance ribbons to each element and any number of elements may be arranged within a housing structure to form the complete heating structure. With my arrangement a plurality of resistance ribbons can be very readily accommodated in the sheath and by means of the terminal structures the resistance ribbons of one element or-of a group of elements may be connected by suitable controlling switches in -various combinations to produce hi h, low, or intermediate heating. In addition to the saving of metal there is also a saving in labor as the parts of the element can be very readily and quickly assembled.

It is evident that a terminal structure may be applied to only one end of the sheath to receive the adjacent ends of the filaments whose opposite ends may be connected together within the sheath.

I do not desire to be limited to the exact construction and arrangement shown and described, as modifications can be made which would still come within the scope of the invention.

I claim as follows:

1. In an electric heating unit of the class described, the combination of a sheath, a resistance filament extending through said sheath, transverse supporting blocks receiving between them an end of said sheath and detachably clamped thereto, terminal connectors on one of said blocks, the ends of said resistance filament extending around said block and connected with said terminal connectors.

2. In an electric heat unit of the class described, the combination of a sheath, a resistance filament extending through said sheath, a terminal structure at each end of said sheath, each structure comprising a pair of blocks of insulating material and means for clamping said blocks together to receive the respective ends of said sheath, connectors on each structure, the ends of said resistance filament extending from the sheath ends to the respective connectors and electrically connected therewith.

3. In an electrical heating element of the class described, the combination of a metal sheath, a resistance filament extending through said sheath, terminal structures each comprising opposed blocks of insulating material, depressions in the opposed faces of said blocks forming pockets for receiving the respective ends of said sheath, clamp ng screws extending through the ends of the blocks for securely drawing them together to rigidly clamp the sheath ends, terminal connectors on said blocks, the ends of said resistance filament extending from said sheath ends and electrically connected with said terminal connectors.

4. In an electric heat element of the class described, the combination of a protecting sheath, a resistance filament extendin through said sheath, terminal blocks secure on the ends of said sheath, terminal connectors on said blocks, and terminal straps extending from the ends of the resistance filament around said blocks and connected with said connectors.

5. In an electric heat element of the class I described, the combination of a protecting sheath, a plurality of resistance filaments extending longitudinally through said sheath, terminal blocks extending transversely across the ends of said sheath and secured thereto, terminal connectors on each block, and terminal straps connected at their inner ends with the ends of the resistance filaments and extending around said blocks and connected with said terminal con nectors.

In witness whereof, I hereunto subscribe my name this 29th day of September A. D., 1923.

THOMAS C. RUSSELL. 

